Chicago ? Authorities investigating the disappearance of a former suburban Chicago police officer’s wife have obtained a warrant seeking information to identify who sent a racy text message to her cell phone.

Drew Peterson’s attorney, Joel Brodsky, said Thursday that a message sent to Stacy Peterson’s cell phone in September shows she was having an affair and lends credence to Drew Peterson’s contention she left him for another man.

“This is obviously sent by a lover of Stacy prior to her disappearance. Drew did not send it,” Brodsky said of the text message he said was sent Sept. 20.

Stacy Peterson vanished Oct. 28. In November, police labeled the 23-year-old’s disappearance a possible homicide and named Drew Peterson, a former Bolingbrook police sergeant, a suspect.

In the message, the author referred to Stacy Peterson in a two-sentence message as “my love” and thanked her for a sexual encounter the previous evening, according to a transcript.